How to make a lightning outlet with your own hands. The best way to protect your cottage from lightning is to install a lightning rod yourself. Main indicators of protection of a country house

Sometimes owners of private houses think about how to protect themselves and their home from lightning strikes. After all, there are regions where the intensity of thunderstorms ranges from 80 hours per year. Therefore, there is a need to install a lightning rod. And this may require additional costs. But you can always make a lightning rod at your dacha or in a private house with your own hands.

You must understand that any lightning rod will only operate at a certain distance and will only protect the space around it. It is necessary to install it in such a way that this zone includes all buildings located on the site, thereby ensuring their protection from lightning.

There are different degrees of reliability of a lightning rod - type A and type B. In this case, we are talking about the protection zone. The first type protects by 99.55% and is defined as the most reliable, the second - by 95%. There is a term “conditional zone boundary” - here the reliability will be the weakest.

Zone defense can be calculated. The parameters will depend on the type and height of the lightning rod. Suppose a single lightning rod is mounted on it, having a height (h) of 150 meters. If you imagine this using a diagram, the lightning rod protection zone looks like a cone. Let's look at the formulas and example of calculation:

Knowing the height of the lightning rod, you can calculate the values ​​of R x, R o and h o.

For zone A the calculation will look like this: h o = 0.85h; R o = (1.1-0.02)h; R x = (1.1-0.02)*(h-h x /0.85).

For zone B: h o = 0.92h; R o = 1.5h; R x = 1.5(h – h x /0.092).

Where h o is the height of the cone, R o is the radius at ground level, h x is the height of the building, R x is the radius at the height of the building.

This formula can also be used to calculate other unknowns. For example, we need to know the height of the lightning rod, but we know the values h x And R x, then for type B the calculation will look like this:

h = R x + 1.63h x /1.5.

Carrying out such a calculation is not at all difficult, but it will guarantee that your home is reliably protected from thunderstorm lightning strikes.

Device

In order to build a lightning rod, the following elements are needed:

• lightning rod,
• down conductor,
• ground electrode.

Lightning rod looks like a metal rod. It will rise above the roof and receive direct lightning strikes, providing protection to the house and withstanding high voltage loads. The best material is strip or round steel with a cross-sectional area of ​​at least 60 sq. mm. There are also requirements for the length of such a lightning rod - the rod must be greater than or equal to 20 cm. It must be placed exclusively in a vertical position. It is best to choose the highest point of the building as a location.

Down conductor is a thick wire with a diameter of 5-6 mm. A good material would be galvanized steel. The down conductor is located in a place where lightning is expected to strike. For example, such a place could be a ridge or the edge of a pediment. The down conductor is not attached very close to the building. It is necessary to leave a distance of 15-20 cm. If we are talking about a roof made of flammable materials, then you need to be especially careful and be sure to leave a gap. Staples, nails or clamps can be used as fastening elements.

Ground electrode necessary to go into the ground. When choosing a material, you need to take into account that this element should easily conduct an electric charge, so you should choose the material that will have a minimum resistance value. It is located at some distance from the porch of the house - at least five. Also, you should not place it near paths and other places where people are often found. To finally make sure that it will not harm anyone, it can be fenced off. It is necessary to retreat from the ground electrode at least 4 meters, placing the fence along a radius. In good weather there is no harm in it, but during a thunderstorm it can be dangerous to be near it. As already mentioned, the ground electrode is installed in the ground. But you need to decide how deep to install it for each case individually. The criteria by which this is done are the following: soil type and availability of groundwater.

For example, for dry soil with a low groundwater level, it is usually mounted from two rods, the length of which is 2-3 meters. These rods must be fixed to a lintel with a cross-sectional area of ​​100 sq. mm. Next, we fix the workpiece by welding to the down conductor and immerse it in the ground at least half a meter.

If the soil is wet or peaty, and the groundwater is close enough to the surface and it is not possible to drive the ground electrode half a meter in, then it should be made from metal corners that are immersed horizontally into the ground to a depth of 80 cm.

DIY lightning rod

If we are talking about multi-story construction, then the installation of the lightning rod is carried out by specialists. Such structures also have a protection zone radius, which allows them to be placed on every building. Before installation, they check whether the building is protected by existing lightning rods or whether a new one needs to be installed.

At a dacha or in a private house, such issues are resolved exclusively by the owners themselves. There are building placement factors that can, to some extent, protect you from lightning strikes. For example, if the house is located along the terrain in the lowest place. In addition, a building located next to yours, which has a large height, can take the blow. And a lightning rod located on your neighbor’s house may protect you from harm. Therefore, one cannot be firmly sure that a house that does not have one is at risk.

If you have examined your and neighboring areas and have not found such protection, then it is best to worry about creating it yourself. Houses that use steel sheets as roofing are of great danger. Behind the attractive appearance lies the problem of lack of grounding. As a rule, such a roofing covering is mounted on a wooden sheathing or roofing felt, which contributes to the accumulation of electrical charge from the atmosphere. Such a device can discharge after a thunderstorm during normal contact with a person, passing a current of several thousand volts. We must not forget that lightning can give a spark, from which wood can so easily ignite.

To protect yourself from fire and death, grounding must be provided every 20 m. In the case of a metal roof, you can do without a lightning rod. The roofing material itself will become an excellent lightning rod.

Tree as a lightning rod

You can save a building from lightning charges not only by installing a lightning rod on the roof. Installing it on a tall tree will also help, provided that it is located at a distance of at least 3 m from your house and 2.5 times higher than it.

To construct such a structure you will need wire with a diameter of 5 mm. One end of it must be buried in the ground, having previously been welded to the ground electrode. The other end of the wire will be a lightning rod. It is placed at the top of the tree.

If there is no tall tree on the site, then a mast with a lightning rod and two metal rods, which are installed at opposite ends of the roof, can help. In this case, a drain is used as a down conductor. It is important that it is made of metal. But here, too, you should not forget about the device of the ground electrode.

Important: When installing a ground electrode, its resistance to electric current should be no more than ten ohms.

Whatever method of installing the lightning rod you choose, it is worth remembering that its high-quality installation will provide you with a comfortable stay only if you periodically check its condition. For proper operation, it is necessary to ensure that all connections are not broken.

Dear readers! The instructions are voluminous, so for your convenience we have made navigation through its sections (see below). If you have questions about the selection, calculations and design of grounding and lightning protection systems, please write or call, they will be happy to help!

Introduction - about the role of grounding in a private house

The house has just been built or purchased - in front of you is exactly the cherished home that you recently saw in a sketch or photograph in an ad. Or maybe you have been living in your own home for several years now, and every corner in it has become home. Having your own personal home is wonderful, but along with the feeling of freedom, you also get a number of responsibilities. And now we will not talk about household chores, we will talk about such a necessity as grounding for a private home. Any private home includes the following systems: electrical network, water supply and sewerage, gas or electric heating system. Additionally, a security and alarm system, ventilation, a “smart home” system, etc. are installed. Thanks to these elements, a private home becomes a comfortable living environment for a modern person. But it really comes to life thanks to the electrical energy that powers the equipment of all the above systems.

The need for grounding

Unfortunately, electricity also has a downside. All equipment has a service life, each device has a certain reliability built into it, so they will not work forever. In addition, during the design or installation of the house itself, electrical, communications or equipment, errors can also be made that can affect electrical safety. For these reasons, part of the electrical network may be damaged. The nature of accidents can be different: short circuits may occur, which are turned off by automatic switches, or breakdowns may occur on the housing. The difficulty is that the breakdown problem is hidden. The wiring was damaged, so the body of the electric stove was energized. If grounding measures are incorrect, the damage will not manifest itself until a person touches the stove and receives an electric shock. Electrocution will occur due to the fact that the current seeks a path into the ground, and the only suitable conductor is the human body. This cannot be allowed.

Such damage poses the greatest threat to human safety, because in order to detect it early, and therefore to protect against it, it is imperative to have grounding. This article discusses what actions need to be taken to organize grounding for a private home or cottage.

The need to install grounding in a private house is determined by the grounding system, i.e. the neutral mode of the power source and the method of laying the neutral protective (PE) and neutral working (N) conductors. The type of power supply network - overhead or cable - may also be important. Structural differences in grounding systems allow us to distinguish three options for power supply to a private home:

The main potential equalization system (BPES) combines all large current-carrying parts of the building, which normally do not have electrical potential, into a single circuit with the main grounding bus. Let's consider a graphic example of implementing a control system in an electrical installation of a residential building.

First, let's look at the most progressive approach to electrical power at home - the TN-S system. In this system, the PE and N conductors are separated throughout, and the consumer does not need to install grounding. You just need to connect the PE conductor to the main grounding bus, and then connect the grounding conductors to electrical appliances from it. Such a system is implemented both by cable and overhead line; in the case of the latter, VLI (insulated overhead line) is laid using self-supporting wires (SIP).

But not everyone has such happiness because the old overhead transmission lines use the old grounding system - TN-C. What is its peculiarity? In this case, PE and N along the entire length of the line are laid with one conductor, which combines the functions of both the neutral protective and neutral working conductors - the so-called PEN conductor. If previously it was allowed to use such a system, then with the introduction of the PUE 7th edition in 2002, namely clause 1.7.80, the use of RCDs in the TN-C system was prohibited. Without the use of an RCD, there can be no talk of any electrical safety. It is the RCD that turns off the power if the insulation is damaged as soon as it occurs, and not at the moment when a person touches the emergency device. To meet all necessary requirements, the TN-C system must be upgraded to TN-C-S.

In the TN-C-S system, a PEN conductor is also laid along the line. But, now, paragraph 1.7.102 of the PUE 7th ed. says that at the overhead line inputs to electrical installations, repeated grounding of the PEN conductor must be performed. They are carried out, as a rule, at an electrical pole from which the input is made. When re-grounding, the PEN conductor is divided into separate PE and N, which are brought into the house. The re-grounding norm is contained in clause 1.7.103 of the PUE 7th ed. and is 30 Ohm, or 10 Ohm (if there is a gas boiler in the house). If grounding at the pole is not completed, you must contact Energosbyt, whose department is responsible for the electric pole, distribution board and entry into the consumer’s house, and point out the violation that must be corrected. If the distribution panel is located in the house, the PEN separation should be done in this panel and the re-grounding should be done near the house.

In this form, TN-C-S is successfully operated, but with some reservations:

• if the condition of the overhead line causes serious concern: the old wires are not in the best condition, which creates a risk of breakage or burnout of the PEN conductor. This is fraught with the fact that there will be increased voltage on the grounded housings of electrical appliances, because the current path into the line through the working zero will be interrupted, and the current will return from the bus on which the separation was performed through the neutral protective conductor to the device body;
• If there are no repeated groundings on the line, then there is a danger that the fault current will flow into a single re-grounding, which will also lead to an increase in the voltage on the frame.

In both cases, electrical safety leaves much to be desired. The solution to these problems is the TT system.

In the TT system, the PEN conductor of the line is used as a working zero, and individual grounding is performed separately, which can be installed near the house. Clause 1.7.59 PUE 7th ed. stipulates the case when it is impossible to ensure electrical safety and allows the use of the TT system. An RCD must be installed, and its correct operation must be ensured by the condition Ra*Ia<=50 В (где Iа - ток срабатывания защитного устройства; Ra - суммарное сопротивление заземлителя). «Инструкция по устройству защитного заземления» 1.03-08 уточняет, что для соблюдения этого условия сопротивление заземляющего устройства должно быть не более 30 Ом, а в грунтах с высоким удельным сопротивлением - не более 300 Ом.

How to ground a house?

The purpose of grounding for a private home is to obtain the required grounding resistance. For this purpose, vertical and horizontal electrodes are used, which together must ensure the necessary spreading of current. Vertical grounding electrodes are suitable for installation in soft soil, while their burial in rocky soil is very difficult. In such soil, horizontal electrodes are suitable.

Protective grounding and lightning protection grounding are carried out in common; one ground electrode will be universal and serve both purposes, this is stated in paragraph 1.7.55 of the PUE 7th ed. Therefore, it will be useful to learn how to unify lightning protection and grounding. To clearly see the installation process of these systems, the description of the grounding process for a private house will be divided into stages.

A separate point should be made about protective grounding in the TN-S system. The starting point for grounding installation will be the type of power system. The differences in power systems were discussed in the previous paragraph, so we know that for the TN-S system there is no need to install grounding, the neutral protective (grounding) conductor comes from the line - you just need to connect it to the main grounding bus, and the house will be grounded. But one cannot say that a house does not need lightning protection. This only means that we, without paying attention to stages 1 and 2, can immediately move on to stages 3-5, see below
TN-C and TT systems always require grounding, so let's move on to the most important thing.

Protective grounding is installed at a pole or at the wall of the house, depending on where the PEN conductor is separated. It is advisable to locate the ground electrode in close proximity to the main ground bus. The only difference between TN-C and TT is that in TN-C the grounding point is tied to the PEN separation point. The grounding resistance in both cases should be no more than 30 Ohms in soil with a resistivity of 100 Ohm*m, for example loam, and 300 Ohms in soil with a resistivity of more than 1000 Ohm*m. The values ​​are the same, although we rely on different standards: for the TN-C system 1.7.103 PUE 7th edition, and for the TT system - on paragraph 1.7.59 of the PUE and 3.4.8. Instructions I 1.03-08. Since there are no differences in the necessary measures, we will consider general solutions for these two systems.

For grounding, it is enough to drive a six-meter vertical electrode.

This grounding turns out to be very compact; it can be installed even in the basement; no regulatory documents contradict this. The necessary actions for grounding are described for soft soil with a resistivity of 100 Ohm*m. If the soil has a higher resistance, additional calculations are required, contact ZANDZ.ru technical specialists for help in calculations and selection of materials.

If a gas boiler is installed in the house, then the gas service may require grounding with a resistance of no more than 10 Ohms, guided by clause 1.7.103 of the PUE 7th ed. This requirement must be reflected in the gasification project.
Then, to achieve the standard, it is necessary to install a 15-meter vertical grounding conductor, which is installed at one point.

It can also be installed at several points, for example, at two or three, then connected with a horizontal electrode in the form of a strip along the wall of the house at a distance of 1 m and at a depth of 0.5-0.7 m. Installation of the ground electrode at several points will also serve the purpose of lightning protection To understand how, let’s move on to its consideration.

Before installing grounding, you need to immediately decide whether the house will be protected from lightning. So, if the configuration of the ground electrode for protective grounding can be any, then the grounding for lightning protection must be of a certain type. At least 2 vertical electrodes 3 meters long are installed, united by a horizontal electrode of such length that there is at least 5 meters between the pins. This requirement is contained in paragraph 2.26 of RD 34.21.122-87. Such grounding should be installed along one of the walls of the house; it will be a kind of connection in the ground of two down conductors lowered from the roof. If there are several down conductors, the correct solution is to lay a grounding loop for the house at a distance of 1 m from the walls at a depth of 0.5-0.7 m, and at the junction with the down conductor, install a vertical electrode 3 m long.

Now it’s time to find out how to make lightning protection for a private home. It consists of two parts: external and internal.

Carried out in accordance with SO 153-34.21.122-2003 “Instructions for the installation of lightning protection of buildings, structures and industrial communications” (hereinafter referred to as SO) and RD 34.21.122-87 “Instructions for the installation of lightning protection of buildings and structures” (hereinafter referred to as RD).

Buildings are protected from lightning strikes using lightning rods. A lightning rod is a device that rises above the protected object, through which the lightning current, bypassing the protected object, is discharged into the ground. It consists of a lightning rod that directly absorbs the lightning discharge, a down conductor and a grounding conductor.

Lightning rods are installed on the roof in such a way that a protection reliability of more than 0.9 CO is ensured, i.e. the probability of a breakthrough through the lightning rod system should be no more than 10%. For more information about what reliability of protection is, read the article “Lightning protection of a private home”. As a rule, they are installed along the edges of the roof ridge if the roof is gable. When the roof is mansard, hipped or even more complex in shape, lightning rods can be attached to chimneys.
All lightning rods are connected to each other by down conductors; the down conductors are connected to a grounding device that we already have.

Installing all these elements will protect the house from lightning, or rather from the danger posed by its direct strike.

Protecting your home from surge voltages is done using an SPD. For their installation, grounding is necessary, because the current is diverted into the ground using neutral protective conductors connected to the contacts of these devices. Installation options depend on the presence or absence of external lightning protection.

1. There is external lightning protection
   In this case, a classic protective cascade is installed from devices of classes 1, 2 and 3 arranged in series. A class 1 surge protector is mounted at the input and limits the direct lightning strike current. A class 2 surge protector is installed either in the input panel or in the distribution panel, if the house is large and the distance between the panels is more than 10 m. It is designed to protect against induced overvoltages, it limits them to a level of 2500 V. If the house has sensitive electronics, then It is advisable to install a class 3 surge protector that limits overvoltages to a level of 1500 V; most devices can withstand this voltage. A class 3 surge protector is installed directly next to such devices.
2. There is no external lightning protection
   A direct lightning strike into a house is not taken into account, so there is no need for a class 1 SPD. The remaining SPDs are installed in the same way as described in paragraph 1. The choice of SPD also depends on the grounding system; to be sure of the correct choice, contact ZANDZ.ru technical specialists for help.

The figure shows a house with installed protective grounding, an external lightning protection system and a combined SPD of class 1+2+3, intended for installation in a TT system.

Comprehensive home protection: protective grounding, external lightning protection system and
combined SPD class 1+2+3, intended for installation in a TT system
(click to enlarge)

Enlarged image of a switchboard with an installed surge protector for a home
(click to enlarge)

No.	Rice	vendor code	Product	Qty
Lightning protection system
1		ZANDZ Lightning rod-mast vertical 4 m (stainless steel)	2
2		GALMAR Holder for lightning rod - mast ZZ-201-004 to the chimney (stainless steel)	2
3		GALMAR Clamp for lightning rod - mast GL-21105G for down conductors (stainless steel)	2
4		GALMAR Copper-plated steel wire (D8 mm; coil 50 meters)	1
5		GALMAR Copper-plated steel wire (D8 mm; coil 10 meters)	1
6		GALMAR Downpipe clamp for down conductor (tinned copper + tinned brass)	18
7		GALMAR Universal roof clamp for down conductor (height up to 15 mm; galvanized steel with painting)	38
8		GALMAR Facade/wall clamp for down conductor with raised surface (height 15 mm; galvanized steel, painted)	5
9

Lightning is one of the most terrible enemies for a private home. Its destructive power is so great that you can lose your home in a matter of seconds. Of course, lightning striking a house is not the most common cause of property loss. Many people are simply lucky enough to live near lightning rods, power lines or high towers. However, as long as there is a danger of sudden and complete destruction of all property, it is hardly possible to live in peace.

The probability of lightning striking a house increases many times over if it is located on a hill or near bodies of water. In such cases, the implementation of a lightning protection circuit mandatory during construction work. SNiP classifies all private buildings as buildings with a third fire safety class, which means they are subject to mandatory lightning protection. As a rule, lightning protection is designed together with the house and installed during its construction.

How necessary is lightning protection for a private home?

To properly build lightning protection, you need to know the nature of lightning. Due to the accumulation of a large electrical charge in rain clouds, an impulse of enormous force occurs, in other words, a discharge of electric current at the highest point on the terrain.

The current strength of an electric discharge during a lightning strike reaches 100 thousand amperes, and in some cases up to 200 thousand amperes. Every second, about two hundred lightning strikes occur on the planet. Even if we take into account that the probability of it hitting a particular house is not so great, it is still better to secure your home in advance and install a structure that protects the house from a lightning strike.

During the passage of an electrical discharge Colossal thermal energy is released through the materials of the house, which causes fires and destruction. As you know, most suburban buildings are built from wooden materials, and they are most at risk of rapid fire.

Based on this, lightning protection of a house becomes an important and mandatory task during its construction. Moreover, regardless of the location of a residential building in the city or outside it and the types of building materials used for its construction, there must be lightning protection.

Operating principles and types of lightning protection

Lightning protection for a private home can be of two types:

1. Active.
2. Passive.

Traditionally, the first type of protection is used - passive, which consists of an lightning rod, a current outlet and grounding. The principle of operation of such protection is very simple. Lightning striking the receiver passes through a lightning rod, which directs the discharge into the ground. When designing any lightning protection system, it is necessary to take into account the characteristics of the material from which the roof is made, the roof structure and its features.

Active lightning protection works on a slightly different principle. The electric current discharge is intercepted by a lightning rod, which creates an ionized field around itself, attracting lightning. Further, the operating principle is identical to passive protection. At the same time, its active type operates within a radius of up to one hundred meters, while its passive type protects only the house itself.

Active lightning protection is the most preferable and is installed in many countries to protect the house and the entire surrounding area. However, it has a high cost, so its installation may not always be advisable.

Do-it-yourself lightning protection of a private house

You can ensure the safety of a residential building with the help of lightning protection made by yourself. The lightning rod circuit is quite simple, it’s easy to do it yourself. Any similar security system for a private home is based on the manufacture of a lightning rod from available building materials.

Any lightning rod has three main components, as shown in the diagram:

1. Lightning rod.
2. Down conductor.
3. Ground loop.

Lightning rods

A metal conductor whose task is to absorb the electrical discharge of lightning is called an lightning rod. It is installed at the highest point of the roof, while on a roof with a complex structure, several such lightning rods are installed.

According to its design features lightning rods can be of several types:

• metal pin;
• metal cable;
• metal grid.

Metal pin

With this method of lightning protection at home, a metal pin is made, from 20 centimeters to one and a half meters long. It should be mounted on the highest point of the roof of a private house.

The material used is copper or galvanized steel due to its high resistance to oxidation. Such a pin can have any shape. The cross-sectional area should not be less than 100 m2. If the pin is round in shape, then its diameter must be at least 12 millimeters. It is possible to use a hollow pipe, but in this case its diameter must be slightly larger, and the end facing upward must be welded. This is a way to protect your home from lightning Suitable for any type of metal roof, including metal tiles.

Metal cable

A device with a metal cable is also quite easy to make with your own hands. The entire structure consists of a cable and a pair of supports, which can be made of metal. However, in this case they will have to be isolated.

A steel cable with a diameter of at least 12 mm is pulled along the roof ridge and secured at the edges. The cable should be at a height of 1–2 meters from the roof ridge.

Metal grid

Lightning rod with receiver made of metal mesh is the best protection option for a tile roof.

When installing the mesh, it is attached along the roof ridge with branches from down conductors that have reliable grounding throughout the entire roof area.

All lightning rods on the roof must be connected to stairs, gutters and any other metal objects.

When large and tall trees grow next to a private house in the immediate vicinity, you can use one of them as a lightning rod. To do this, the metal pin should be installed so that it is one and a half meters higher than the tree crown, and then connected to the down conductor. An important condition is the height of the tree- it should be 10–20 cm higher than the house.

Creating a down conductor

A down conductor is one of the components of a lightning rod, which is responsible for conducting an electrical discharge from the lightning rod to the ground loop. It is made of steel wire with a diameter of at least 6 mm. One end of it is welded to the base of the lightning rod, and the other to the ground loop. Special attention must be paid to the quality of welding to avoid breakage at the fastening point. The current that passes through the down conductor can reach 200,000 amperes.

The down conductor must be secured along the contour of the roof and house using insulators at a distance of 2–3 cm from the roof and walls . If there are several down conductors, then the distance between them should be at least 25 meters.

Do not fasten the wire near doors or doorways. When installing, avoid sharp bends and places where it could be damaged by snow or debris. The down conductor should be as short as possible, and it should be located in places with the greatest risk of lightning strikes: on sharp protrusions, edges of gables, etc.

Lightning rod grounding

A ground loop completes any lightning protection device design. Its task is to ensure reliable contact of the entire device with the ground. Externally the structure looks like three large electrodes that are interconnected and recessed into the ground.

To assemble the device responsible for grounding, you will need steel with a cross-section of 80 m2 or copper with a cross-section of 50 m2. In a pre-dug trench, about one meter deep and 3 meters wide, you need to drive two metal rods made of copper or steel along the edges. Then they are connected to each other by welding and a down conductor from the house is welded to them. The entire structure is driven to the ground into the ground.

When assembling the grounding device, you need to remember that it must be located no closer than five meters from doors or windows, passages, porches and paths. Distance from the walls of the house must be at least one meter.

Lightning protection care

Every year before the start of the thunderstorm season, special attention should be paid to preventive inspection of lightning protection at home. All components of the lightning rod and mounting points must be inspected and, if necessary, painted or repaired.

Every three years it is necessary to conduct a major inspection of the entire system. Check the connections between the down conductor and the ground loop, clean and tighten the contacts there. Defective clamps - replace.

Every five years, the ground loop electrodes are inspected. To do this, they need to be removed from the ground and carefully checked for corrosion. If due to this reason the cross-section of the electrodes has decreased by more than a third, then they should be replaced.

The need to install a lightning protection system for a private home is determined by the owner of the building based on the likelihood of the object being struck by lightning and possible material damage. National regulatory documents do not impose requirements for the mandatory implementation of the MH system for individual residential buildings.

The likelihood of a lightning strike on an object depends primarily on the duration of thunderstorms in the area where it is located.

For a rectangular house with dimensions of 10x12 m and a height at the ridge of 8 m, this relationship is shown in the table:

The complex of lightning protection means for buildings includes devices for protection against direct lightning strikes (external lightning protection system) and devices for protection against secondary effects of lightning (internal lightning protection system). In particular cases, lightning protection may contain only external or only internal devices.

The external lightning protection system protects directly from a direct lightning strike on an object. This impact is dangerous primarily due to the high temperature of the lightning channel, which can lead to fire of combustible building structures.

You can learn more about the dangers posed by a lightning strike in the series of articles “Lightning Protection for Beginners” by Professor E. M. Bazelyan.

Composition and design of components of an external lightning protection system

The external lightning protection system consists of three components: lightning rods that absorb a direct lightning strike; a grounding device that ensures the flow of current in the ground, and down conductors that communicate between the first two elements.

Lightning rods

The choice of the number and height of lightning rods should be made by calculating protection zones. The design protection zone of installed masts must include the entire volume of the protected object.

The protection zone of a rod lightning rod is a cone, the top of which coincides with the vertical axis of the mast. The dimensions of this cone depend on the required reliability.

The dimensions of the protection cone in accordance with SO 153-34.21.122-2003 “Instructions for the installation of lightning protection of buildings, structures and industrial communications” for a reliability of 0.9 are determined by the formulas:

Installing a free-standing mast to protect a house will not be advisable, due to the fact that its height must be substantial (up to 30 meters). This is not only expensive and labor-intensive, but also increases the total number of lightning strikes to the area of ​​land in question. It would be optimal to place masts directly on the protected object.

Installing one mast may only be sufficient for a house with a hip (pyramid) roof when placing the mast at the top of the roof.

For a rectangular house with a gable roof (roof slope angle of at least 35°), for reliable protection it is necessary to install two masts 2 meters high along the edges of the roof ridge. For a house of a more complex shape, it is necessary to carry out calculations taking into account the structurally possible locations for installing lightning rods.

Lightning rods must be made of materials and dimensions (sectional area, thickness) corresponding to GOST R IEC 62561.2-2014.

Down conductors

The diameter of down conductors made of round steel must be at least 8 mm. Down conductors must be positioned in such a way that between the point of damage and the ground, the current spreads along several parallel paths, and the length of these paths is minimal. It is recommended to lay down conductors at the maximum distance from doors and windows.

Direct contact of a down conductor of the required cross-section with the material of the walls and roof cannot lead to fires, due to the fact that the increase in the temperature of the down conductor under the influence of lightning current is not enough even to begin the process of charring wood, not to mention other low-flammable materials. In addition, the thermal effect is very short-lived.

Grounding device

In all possible cases, it is necessary to use metal foundation piles or interconnected reinforcement of reinforced concrete building foundations as a grounding device. This solution is applicable if connection is possible (presence of fittings outlets) and when bitumen and bitumen-latex coatings are used as waterproofing. Epoxy and other polymer coatings prevent electrical contact between the foundation and the ground, and, therefore, this foundation cannot be used as a natural ground electrode.

Artificial ground electrodes should be located under asphalt pavement or in rarely visited places away from pedestrian roads.

The grounding device to which the lightning rod is connected must have the following minimum design:

Three or more vertical electrodes with a length of at least 3 meters, united by a horizontal electrode, with a distance between the vertical electrodes of at least 5 meters.

Grounding electrodes should be located outside the protected object and be as distributed as possible. The preferred depth of electrodes is at least 0.5 m, the distance from the walls of the object is 1 meter.

The dimensions of grounding conductors must meet the requirements of corrosion and mechanical resistance. Regulatory documents (GOST R 50571.5.54-2011) provide the minimum dimensions of electrodes depending on the material from which they are made.

Notes

* The probable number of lightning strikes per year for an object is calculated using following formula:

Where:
A - building length, m
B - building width, m
H - building height, m
n - average annual number of lightning strikes per 1 km 2 of the earth’s surface, 1/(km 2 *year)

The specific density of lightning strikes into the ground n is determined based on the average annual duration of thunderstorms in hours as follows:

Lightning strike period:

External lightning protection components

Traditional vertical lightning rod in the form of a two-meter (GL-21101G) or four meter (GL-21103G) mast, comes with a screw-on sharp tip.

The mast is made of stainless steel in the form of a pipe with a wall thickness of 2 mm.

	GL-21101G	GL-21103G
Weight:	5 kg	10 kg
Height:	2000 mm	4000 mm
Lightning rod diameter:	35 mm	35 mm
Wall thickness:	2 mm	2 mm

The clamp allows you to quickly attach a down conductor wire with a diameter of 8 mm to the façade/wall of a building.

A clamp with a rubber sealing sleeve allows you to quickly secure a down conductor wire with a diameter of 8 mm on a roof covered with a metal profile / corrugated sheet.

There is NO screw included (example in the photo).

A clamp with the ability to disconnect the external lightning protection system (down conductors) from the grounding device (for example, for taking measurements). Allows you to connect down conductors made of D8 wire in a straight line.

ZANDZ and GALMAR

GALMAR and ZANDZ grounding rods are made of steel coated with a protective copper coating with a thickness of at least 0.250 mm, which ensures a guaranteed service life of the device of up to 100 years.

The design of the rods, which can be interconnected and immersed in the soil to a depth of 40 meters, ensures low grounding resistance in a small area. Installation is carried out by one person without the use of construction and specialized equipment.

Modular grounding can be purchased both in the form of ready-made kits and in the form of separate components.

You can find detailed information about modular grounding technology on a separate page.

An example of lightning protection for a private house based on GALMAR and ZANDZ products

On the right side of the page there is a list of products, using which you can organize a complete system of external lightning protection. All offered products comply with the requirements of national regulations for minimum dimensions, contact connection quality, mechanical strength, service life, etc.

Lightning rods are mounted on vertical surfaces of walls or chimneys, ventilation shafts. When placing masts, you should take into account the size of the overhang of the roof slope over the walls and check the possibility of using holders 21101G/21102G.

Most of the clamps for down conductors are available in two versions: galvanized painted steel and copper. The current conductor is fastened using clamps in increments of 1 meter. The type of clamps is selected based on the placement surface (roof: flat, slope, ridge; facade, etc.) and its material (metal profile, natural tiles, etc.). Please note that façade and roofing clamps do not come with anchor bolts. Their type and length must be selected depending on the base material.

It is also possible to attach the down conductors to the drainage system of the house (attachment to a gutter, pipe).

The grounding device is assembled from components of a modular grounding system.

The roofing material is metal tiles, the wall material is wooden beams.
A=10 m; B=8 m; H=8 m; α=35°;
Nkr=3.5 m; Nst=4.5 m; Lsk=6.1 m

Lightning rods are connected to each other to organize two down conductors from each lightning rod.

If you have any difficulties in calculating or selecting components, you can always contact our technical center for help.

From a school physics course we know that lightning is a huge electrical discharge that carries a lot of thermal energy. The consequences of a lightning strike can be catastrophic, so at all times humanity has tried to create devices and devices that would protect them from this natural scourge. In the modern world, lightning protection of a private home is a combination of design features of the building and special devices designed to discharge electricity into the ground. The latter is called a lightning rod, how does it work, what are the requirements for it?

Types of lightning protection

Lightning protection of a home is divided into two categories: internal and external. The purpose of the first is to protect against lightning, the thunderstorm of which did not hit the house itself. For example, it can get into a power line that connects to the house's internal electrical wiring. In this case, high overvoltages occur in the internal electrical wiring. The consequence is the failure of most household appliances. In any case, the one that was plugged into the sockets at that time. The wires may burn out, a short circuit may occur, the worst case scenario is a fire if the wiring was carried out on wooden floors or the house was made of wood.

This problem can be solved by installing special devices in the electrical network that will protect it from surge voltages. For example, surge suppressors, all kinds of arresters, SPD (surge protection device). All devices are installed in the distribution board of the house.

External protection

External lightning protection is a lightning rod, which consists of three main elements:

• lightning rod;
• down conductor;
• ground loop.

The main requirement for all three elements is their reliable connection with each other. Depending on the roofing material, it is necessary to use different types of lightning protection. There are three of them: pin, cable and mesh.

Pin

It is usually used if the roof of the house is covered with metal roofing material. For example, metal tiles, corrugated sheets or tin. To do this, you need to install a metal pin on the roof, which will rise above the ridge of the roof of the house, approximately 1-2 m higher. This will be the lightning rod. It can be made from a metal rod with a diameter of 8-12 mm, or a steel strip 4-5 mm thick and 25-35 mm wide can be used for this.

Such a lightning rod can divert electrical strikes from the elements around a house with an area equal to the area where the radius is the height of the lightning rod. And the higher the pin is installed, the larger the area it protects from lightning strikes.

The removal capacity of an air terminal is not based on the size of the area it covers. If we take into account that the vertical line for installing the pin is the height of the isosceles triangle, then the base of this figure will be two height sizes. It turns out that a circle with a radius equal to the height of the pin installation can form on the ground surface.

Rosovaya

This lightning rod requires a cable that is stretched along the roof ridge, and it is suspended at a height of half a meter above the installation level of the ridge. To do this, it is best to use a cable made of galvanized wires with a total minimum cross-section of 5-7 mm. This lightning protection is used if the roof of the house is covered with slate.

The cable is pulled along the ridge and attached to wooden posts installed along the edges of the ridge beam. If the roof is long, then there may be more racks, the main thing is to maintain a slight slack in the cable. Strong sagging is unacceptable, because this reduces the distance from the roof ridge to the lightning rod. And it should not be less than 1 m. The mounting method is varied, the strength of the installation is important here. You can fasten it with clamps (metal or plastic); if the cable is thin, 5-8 mm, then you can simply tie it and additionally tie it with wire.

Mesh

This is a more complex structure that is installed on roofs covered with tiles. Making such a lightning rod with your own hands is not easy. For this, steel wire rod with a cross section of 6-8 mm is used, which is laid over the entire surface of the roof slopes in the form of a grid with cell sizes of 6x6 m or more, it all depends on the area of ​​the roof. All connections are welded, fastened to the roof using brackets.

As for the down conductor, this is a line connecting the lightning rod to the ground loop. Typically, steel wire rod with a diameter of 6-8 mm is used for this. It is important here that the current-carrying element can withstand high current strength, which often reaches up to 200,000 amperes. If ready-made protection is selected, then its current conductor is copper or aluminum wire with a diameter of 6 mm.

Requirements for down conductors.

1. This should be the shortest path from the lightning rod to the ground loop.
2. When laying, bends and creases should not be used, which, during the removal of electricity, will become the site of the appearance of a spark charge, which, as practice shows, leads to ignition.
3. The laying route is chosen so that the wire does not pass near windows and doors.
4. If a lightning protection device is being installed for a wooden house, then the down conductor is installed at a distance of 15-20 cm from the surfaces of the wooden structure. For this, special staples are used. They are a metal clamp, the base of which is made of hard and durable plastic. It is the plastic that protects the conductive element from contact with the wooden structures of the house. The bracket is attached with self-tapping screws. By the way, these brackets are also used in the construction of a mesh lightning rod, where the distance between them is 1.5-2.0 m.
5. If the protection of buildings and structures from lightning is a large mesh structure, or a long laid cable, or several pins are used on the roof, then there must also be several down conductors, the distance between which is 25 m (according to SO 153-34.21.122-2003).
6. The wire rod is carried along the walls of the building, along the gables and sharp protrusions of the roof. That is, in those areas that can be struck by lightning.

Ground loop

The lightning protection circuit in a private house is carried out according to the same scheme and design as the grounding of electrical networks.

• Trenches are dug in the shape of an equilateral triangle one meter from the foundation of the house and at least five meters from the front door, paths, and platforms. The depth of the trenches is 80 cm, width is 60 cm, length is 1.5-2 m.
• Angle steel pins measuring 50x50x5 mm are driven into the corners of the triangle. The depth of burial is 2-3 m. The corners should not be driven completely into the ground, the height of the free protruding section is 20-30 cm.
• The pins are connected to each other by a steel strip 4 mm thick and 40 mm wide. You can use the same corners for these elements as for the pins.
• This lightning protection grounding circuit is connected to the down conductor.

Attention! All connecting joints must be secured by electric welding. Bolted connections are not recommended, because during operation of the lightning rod of a country house, they can weaken, rust and weaken the conductivity of the entire structure.

DIY assembly

Before making a lightning rod in a private house, you need to decide what type of lightning rod to choose. If this is a pin version, then the pin itself must be installed not on the roofing material, but on the sheathing.

After that, a current-carrying wire is laid with your own hands. If the length of the purchased piece of wire or rod is not enough, then you can connect the two sections using an aluminum or copper contact, which is used in overhead power lines. The distance between brackets is 1.5-2.0 m.

A grounding loop is constructed to which the down conductor is attached. Before welding, all joints of elements must be cleaned to a metallic shine. If ready-made lightning protection for a private building is used, then special devices with bolted connections made of non-ferrous metal are used as connections.

Attention! The best option is to place the grounding and lightning protection circuits close to each other and connect them together with wire rod or strip. This does not violate the standards of lightning protection devices, and the circuit becomes twice as large.

When installing lightning protection in your own private home with your own hands, you need to understand that this is an element of safety not only for the building, but also for the people living in it. Therefore, you should not put off its installation for a long time. The ideal time for installation is to build a private house with your own hands.

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